Now that fragility curve alternatives have been created, the user needs to define the fragility curves and to associate each curve with a failure location on a levee (structure). From the Fragility Curve Editor (Figure 17.1):
1.The user can select from the Randomize every list (Figure 17.13) to have the failure elevations sampled by every event in a realization or sampled once in a realization. The default is to randomize the failure elevations by event.

Figure 17.13 Fragility Curve – Initial Setup
2.From the Levee list (Figure 17.13), the user can filter the list of fragility CCPs. The list will either contain the names of levees that have been included in the HEC-WAT schematic (created in HEC-WAT for visual purposes only and not provided by the RAS model alternative) or the <Not Selected> option. If the user selects the <Not Selected> option, then all of the fragility curve CCPs will be available from the Failure Location list (Figure 17.13).
3. Elevation-probability information, which is used to define a fragility curve (Figure 17.14), can then be entered. The elevations should correspond to the levee structure elevations in the RAS model alternative (plan).

Figure 17.14 Defining a Fragility Curve
4.A fragility curve (within HEC-WAT) is defined as a cumulative distribution function (CDF) where the probability of failure must start at zero (0.0) and span to a probability of one (1.0). Both elevation and probability of failure must be monotonically increasing.
5.By right-clicking on the table that defines fragility curves, a shortcut menu will display (which is shown in the figure to the right). From this shortcut menu, the user can cut/copy/paste items; clear selected cells; select all cells; delete rows; print the table; and export the table.
6.The user can fill cells that have been selected, from the shortcut menu click Fill, the Table Fill Options dialog box (Figure 17.15). The user has several options to choose from:
● Linear Fill - when selecting the cells, for Linear Fill (Figure 17.18), the first and last rows must have data. Click OK, the Table Fill Options dialog box will close and the table will be filled with linearly interpolated data.
● Repeat Fill - when selecting the cells, for Repeat Fill (Figure 17.15), the user must select a row that contains the data that will be repeated in the other selected rows. Click OK, the Table Fill Options dialog box will close and the table will be filled with repeated data.
● Add Constant - when selecting the cells, for Add Constant (Figure 17.15), the user must select rows that contain data that the user wishes to increase by a constant value. The user will enter a value in the box next to Add Constant. Click OK, the Table Fill Options dialog box will close and the rows selected in table will be filled with data that has been increased by the constant value entered by the user.

Figure 17.15 Table Fill Options Dialog Box
● Multiple Factor - when selecting the cells, for Multiple Factor (Figure 17.15), the user must select rows that contain data that the user wishes to increase by a multiplier. The user will enter the multiplier in the box next to Multiple Factor. Click OK, the Table Fill Options dialog box will close and the rows selected in table will be filled with data that has been increased by the multiplier entered by the user.
7.When the user chooses to Sum Selected Cells or Sum Entire Column from the shortcut menu, a Sum window will open (Figure 17.16) providing the user with the desired information.

Figure 17.16 Sum Window
8.Once the user has entered all of the information for the fragility curve, click OK, the Fragility Curve Editor (Figure 17.1) will close.